BCMB 230 1st Edition Lecture 5 Outline of Last Lecture I Protein Binding Sites II Transcription and Translation III Posttranslational Modification IV Enzymes and Chemical Reactions Outline of Current Lecture I Energy II Cellular Respiration III Anaerobic Respiration IV Protein and Amino Acid Metabolism V Fat Metabolism Current Lecture Metabolic Pathways Glycolysis and Krebs Cycle I Energy Adenosine Triphosphate ATP nucleotide that transfers energy from metabolism to cell function during its breakdown to adenosine diphosphosphate ADP has a lot of high energy bonds in it for lots of processes this is the preferred source of chemical energy for cells energy derived from the hydrolysis of ATP is used by the cells for the production of force and movement muscle contraction active transport of molecules across membranes and the synthesis of the organic molecules used in cell structures and functions make it in our bodies primarily from glucose move energy around body in the form of glucose when it gets to the cell have to change it to ATP the more mitochondria a cell has the more ATP is needs produces proteins and fats can also be used to make ATP can use glucose to make proteins and fat or can use proteins to make glucose II Cellular Respiration Overall reaction of Cellular Respiration C6H12O6 glucose 6O2 oxygen 6CO2 carbon dioxide 6H2O water 38ATP These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute does not go both ways and is not one reaction it is a summary reaction actual process occurs in a series of reactions amount of ATP is typically 38 but depends on which cell in the body we are talking about cellular respiration is lumped into three main sets of reactions glycolysis Krebs Cycle and oxidative phosphorylation also called electron transport cellular respiration occurs in the cells to make ATP Glycolysis Gycolytic pathway pathway that partially catabolizes carbohydrates primarily glucose takes place in the cytoplasm starts with 6 carbon C glucose use 2 ATP to make molecules then split the molecules the 6C structure into two 3C structures called pyruvate get 4 ATP back with a net gain of 2 also get 2 NADH molecules made from NAD which allows you to transfer energy like ATP mainly going to use it as an energy carrier in oxidative phosphorylation to make ATP at the end of glycolysis you have 2 pyruvate 4 ATP and 2 NADH molecules start to get ATP back get 4 ATP back but have a net gain of 2 ATP during glycolysis Linking Step Transition into Krebs Cycle takes place in cytosol make 2 acetyl Co A coenzyme A from pyruvate break off 2 carbon makes 2 carbon dioxides capture energy from breaking bonds in 2 NADH Krebs Cycle takes place in the mitochondria take acetyl coA and make 4 carbon intermediate and then make 6 carbon intermediate then make 5 carbon intermediate then make 4 carbon intermediate then make 6 carbon intermediate etc is a cycle going to completely destroy coA make two carbons off each forms 4 carbon dioxides 6 NADH and 2FADH2 make ATP directly from Krebs Cycles 2 ATP take NADH 10 NADH so far and FADH2 2 so far into Oxidative Phosphorylation Oxidative Phosphorylation have to have oxygen 6 O2 10 NADH and 2 FADH2 as a result get 34 ATP also get 2 FAD and 10 NAD which we recycle back to glycolysis and the Krebs cycle III Anaerobic Respiration Anaerobic without oxygen if oxygen is absent then oxidative phosphorylation stops no longer yielding NAD which then stops glycolysis therefore no ATP is made and no cellular processes can occur Some cells can change pyruvate into lactate in the cytosol instead of continuing into the Krebs cycle lactate is a dead end if it builds up in the cell it can poison it which causes it to not perform efficiently or to even shut down only way to get rid of lactate it is to have oxygen Process use some of the NADH to produce NAD can then use NAD to run second half of glycolysis to make ATP 2 ATP however pyruvate is used up so can t go to Krebs cycle We have to have aerobic respiration glycolysis but anaerobic respiration allows us to make our muscles work a little longer to get us out of a dangerous situation only lasts for a couple of minutes aerobic cellular respiration is required for cells to stay alive anaerobic cellular respiration is primarily for muscle cells short term response associated with fight or flight reflex IV Protein and Amino Acid Metabolism Deamination using protein for energy take amino acid and cut the amino group off leaving a keto acid amino acid without an amino group and ammonia NH3 Ammonia is highly toxic so it is changed to urea in the liver urea is toxic but not as toxic as ammonia so we can tolerate this toxicity more keto acid then is matched with pyruvate or goes into the Krebs cycle determined where it goes by the shape everything is controlled by enzymes whichever enzyme present matches with the keto acid and determines which stage of the cycle it will go to can also take amino acid leads to keto acid and then run glycolysis backwards to make glucose process called gluconeogenesis where amino acid turns into glucose amino acid can also be deaminated and used to make ATP amino acid has to go to pyruvate in order to perform gluconeogenesis if it goes to Krebs cycle it cannot be reversed to acetyl coA Amino acid metabolism don t usually lose proteins amino acids through urine or feces recycle but don t get rid of Oxidative Transamination of Amino Acids Transamination creates amino acids that are in short supply have an amino acid and keto acid keto acid steals the amino group off the amino acid Can do this to make a protein as a byproduct there is a keto acid to replace the one taken out of cellular respiration Essential amino acids all amino acids are needed but essential amino acids have to be in the food we eat because they cannot be synthesized by the body nonessential amino acids can be synthesized other organisms have the gene to synthesize amino acids but humans don t V Fat Metabolism Fats can form into glycerol a 3C molecule that can be used somewhere in glycolysis can be reversed from glycerol to glycolysis or glycolysis to glycerol In order to react in cellular respiration the long carbon chain in fatty acids have to be cut into chunks that will be recognized by acetyl coA enzymes Beta oxidation take fatty acid and cut it apart two carbons at a time and utilize that piece into cellular respiration allows